(a) Field of the Invention
The present invention relates to a device for maintaining height of an active headrest, and more particularly to such a device in which the height at which the headrest is locked varies depending on the amount of force of a vehicle crash.
(b) Description of the Related Art
An active headrest is a general term that refers to a headrest that automatically rises and supports the head of a passenger to protect the passenger's head and neck in a vehicle crash.
A conventional active headrest includes a self locking device. However, the conventional self locking device locks only if the active headrest rises higher than a reference height, keeping the active headrest raised. That is, the height of the active headrest can be maintained only if force of the crash is greater than a reference value.